When the Mad Dog bites
by Kooliez
Summary: Oikawa has always had 2 goals in his life. 1) Getting amusing reactions out of a certain Mad Dog-chan... oh and of course 2) Picking up as many chicks as he can to expand his fanclub empire. Imagine how delighted he is once he realises a chance to achieve both comes wandering in through the gym door one day... Brother!KyoutanixOCxVarious (mainly Oikawa) Rated M for later chapters
**Chapter 1:**

 _Author's Note: My first ever multi-chapter story for the Haikyuu fandom ever! I think I've more or less gotten used to the individual personalities of the characters, so hopefully there won't be any OOC instances… ;w; Well I'll try my best, but I'd appreciate it if you let me know what I'm doing right or wrong so that I can make this story better for everyone xD_

 **Start of Actual Story:**

 **Iwaizumi's POV**

 **THWACK!**

"…!" Closing my eyes and pinching the bridge of my nose, I growled for what felt like the thousandth time of the day as Kyoutani Kentarou spiked a ball that wasn't meant for him _…_ _ **Again**_ _…_

Storming my way over to where Assikawa was already scolding the problematic second year who was ignoring him, I drew back my hand and smacked the blond hard across the back head before drawing breath to begin my own rant "IDIOT! You don't go for a ball that clearly isn't yours _**especially**_ not when it's the set or game point! Now, apologize to Kindaichi for nearly running him over!"

"…"

Muscle jumping slightly in my jaw when I noticed he wasn't even looking at me, I gave a small sigh before following his gaze to the outside of the gym… or, more precisely; the door leading to the exit of the gym.

Vein throbbing in my temple over the fact that he was more interested in getting home than taking the time to reflect on his behavior during today's practice, I gave him another smack, this time grabbing his collar and looking into his startled brown eyes to make sure he was really paying attention before ramming my forehead against his nose with a satisfying crack "Before you go home, you're going to polish all the volleyballs in the gym, got it?!"

"…Osu…" Ignoring the blood which was already starting to erupt from his nose like fireworks, Kyoutani cast the doors of the gym one last look filled with a mixture of… _expectancy and longing…?_ But before I could get another closer look, the temperamental second year had already sauntered off to the gym store room to finish punishment I gave him.

"…Strange…"

Turning to face Oikawa who had watched the whole scene without saying a word, I let a small frown spread over my face at his sudden pronouncement "…What is?"

Resting his chin between his thumb and forefinger, an uncharacteristically serious look on his face as he stared at the door of the gym store room through which Kyoutani had disappeared through moments ago, Oikawa tilted his head slightly as he hummed, apparently deep in thought "…Hmmm… I guess you could say, that reaction just now was really mild of him…" Normally wide brown eyes narrowing slightly to further reflect his confusion, Oikawa chewed his bottom lip thoughtfully "I don't know… just a hunch, but with his reaction just then, it seemed like he was waiting for something… or maybe a someone…" Confused frown instantly morphing into a wide, devious smirk, Oikawa rubbed his hands together conspirationally "…Ne Iwa-chan… Do you reckon that maybe… just maybe…?" Tilting my head in confusion as he beckoned for me to come closer, my eyes widened as he latched both arms around my neck before whispering his theory into my ear "Do you think Mad Dog-chan has a girlfriend?"

"…" Letting my eyes narrow again, I shoved Oikawa off of me, ignoring his cries of pain as an unimpressed expression spread over my face "I highly doubt it, with him being as aggressive as he is." Giving a sigh at the childish pout he was giving me, I reached over to the bench and grabbed 2 mops, tossing one over to Oikawa "Come on Shittykawa, we really need to start cleaning up."

"Hai… Iwa-chan is such a meanie…" still sulking as he turned to mop up the gym, we almost missed the girl that stood waiting patiently at the gym door.

"Erm… Excuse me?"

Immediately spinning around at the sound of the feminine voice, Oikawa gawked… and if I was honest, so did I, because standing there was one of the most petite girls that I had ever seen.

… _ **So cute…!**_

Recovering almost instantly, Oikawa made a beeline for the girl and fluffed up his bangs, preening "Well Hello there, I've never seen you around here before! Are you the Volleyball club's latest fan?" Still smiling, Oikawa reached out presumably to kiss the girl's hand… only to get a punch to the face. Stunned, I traced the fist back to its owner only to find a certain absolutely livid 2nd Year, who, at the moment, fully deserved the nickname of "Mad Dog" that Oikawa had given him.

Lowering his clenched fist as he shoved the girl behind his back protectively, Kyoutani growled as he eyed the downed Oikawa with a mixture of distaste and great dislike. Peering around Kyoutani's side from under his protectively outstretched arm, the girl tilted her head slightly in confusion as her slightly overgrown brown bangs fell messily into her large hazel eyes. Glancing between the moaning Oikawa and visibly enraged Kyoutani, she clung to his arm, giving his jersey a few tugs to get his attention "…Onii-chan…? What's going on…?" _…? Did she just say…?_

Still glowering at the wailing brunet, Kyoutani scowled, giving him one last brutal kick to the side before turning around and grabbing the girl, crouching slightly so his eyes, which were rapidly running up and down her body, missed no potential injuries. Satisfied with the apparent lack of damage, Kyoutani quickly wrapped his arms around the girl, giving her a tight hug as he closed his eyes and roughly, yet undeniably lovingly, pressed his forehead against hers.

Finally pulling away after what felt like a few hours at the very least, the bleached blond leaned down so that he was on the same eye level as the girl, fixing her with a piercing but not unkind gaze as he rested both hands – the same hands capable of spiking a volleyball over the net with the strength and force of a cannon – on her shoulders in a manner that was almost _ **… gentle…**_

"Kaede!? What are you doing here?! I told you to stay home!"

 **Kaede's POV**

Meeting my brother's fearful, almost _desperate_ gaze determinedly, I swept my long brown bangs out of my face and rested my hands over his before gently lifting them off of my shoulders and bringing them back down so that I was holding them in front of me, noting with slight amusement as his eyes traced my actions like a cat contrary to the canine image that he was usually associated with.

Letting a smile spread over my lips at the thought, I slowly lifted a hand up to cup his face before opening my mouth to speak "Onii-chan! You told me that you were finally going to go back to attending volleyball club practice and well… you get set off really easily so I came to check on you!"

Smiling at the way a dull red flush of embarrassment made its way across the bridge of his nose as he determinedly avoided my gaze, I brought my hand away from his cheek before wrapping them tenderly around his neck, letting him rest his chin on my shoulder "Looks like I needn't have worried! You seem to be getting along with everyone just fine, so let's go home and I'll make Famima Chicken for dinner, okey?"

Pulling back slightly so he could meet my gaze, my brother gave a quick nod, face still slightly flushed "…O-Osu… But I want extra breading on mine."

"Hai, hai." Letting a small smile tug at my lips, I failed to notice that the brunet had gotten back up until he shoved my brother out of the way, ignoring his growl of protest before looking me over appraisingly, eying me up and down.

"…Um… may I help you?" I asked nervously, feeling his eyes bore into me as my brother again pushed me behind his tall, muscular 5'10.4 frame, effectively blocking me from view. Fixing the taller brown-haired male with one of his practiced glares before giving off a warning growl, Onii-chan lifted his chin in a subtle, challenging gesture of defiance "Oi, Idiotkawa, mind not staring at my sister like she's a piece of meat on display in a butcher's window? You're making her uncomfortable and you're pissing me off."

Face flushing at his colorful choice of language, I bit my lips, taking one of his hands in mine in an attempt to lead him away before he started another fight on my behalf "…Onii-chan…" But that was all I managed to get out before my brother looked over his shoulder gave my hand a gentle but firm squeeze; his way since our childhood of signaling that he had no intention to back down.

"Not now Kaede, with bastards like him, it's best to sort them out before they get any funny ideas." At the word "bastard" he fixed the fluffy-haired brunet with a look like he'd quite like to see him wither up "I'm only saying this once, Shittykawa, so you better fucking listen up: Stay the hell away from my sister; and if I catch you within a 50 meter radius of her… Make sure you have 119 on speed-dial because one of both of us would be needing it soon." He threatened, eyes narrowing dangerously.

 **(Author's Note: Fun fact! 119 is the emergency number in Japan, so Mad Dog-chan basically told Oikawa to have the hospital and/or the fire brigade on standby XD)**

Petulant pout slowly morphing into a dangerous smirk, the fluffy-faired male stepped closer and closer until he was chest-to-chest with my brother, forcing him to look up due to their height difference "Ara… Looks like Mad Dog-chan needs to learn to respect his Senpais, hmmm?" he smirked, eyes darkening with an unidentifiable gleam.

Holding his ground as he stared back in an extremely agitated manner, Kentarou-nii gave an angry, almost animalistic growl before lifting his chin up even higher, returning Oikawa's smirk with sharp glare shortly followed by a growl "… _Che_ … Check your calendar you manwhore, "Respect for the elderly" day isn't until next month!"

Catching the dangerous glint that flickered past the brunet's narrowed brown eyes, I immediately tugged at my brother's jersey, trying to pull him away "Onii-chan… Come on! Let's go! As soon as we get home, I'll start making the Kara age okey?!" _…I can't quite put my finger on it… but something about that guy screams trouble…_ I thought, eying the 6 foot tall brunet with a scrutinizing gaze _…Something about him seems off… and I really don't wanna be around when that something comes to light…!_ Unfortunately, it seemed that the older male had other plans.

Still smirking as he casually shoved his hands inside his pockets, the brunet tilted his head playfully "Oh my… such filthy words… you have to wonder if Mad Dog-chan has any bite though…" Already dark brown eyes growing even darker still, the brunet's lips twitched into a condescending smirk "So eager to threaten with violence… But don't worry; I'm not that kind of guy, so you'll consider going out with me sometime, right Cutie-chan?" He asked directing his last words at me as he shot me a wink… and that was the last straw for my brother.

Snarling as he lunged towards the brunet, I barely managed to seize the back of my brother's jersey jersey before he potentially murdered the still smirking brunet. Wrapping both arms around one of his, I dug my heels into the gym floor in an attempt to hold him back "ONII-CHAN! That's enough! Let's just go home alright?! We can watch a movie and forget about everything so just… hold back for now okay?" Lifting my head to meet his conflicted gaze, I waited on baited breath as he glanced between the brunet and me, so obviously weighing out his options that I could practically hear the gears turning underneath his bleach blond hair.

"…" Letting out a frustrated sigh through tightly compressed lips, Kentarou-nii contented himself with an ugly grimace and an extremely rude hand gesture, both thrown at the brunet before grudgingly letting me lead him away.

…

…

…

 _~Short time skip to after arriving home~_

 **Kaede's POV**

"ONII-CHAN! Dinner's ready!" I called as I set the table. Getting a grunt in response, I smiled as I heard the slight creaking of my brother getting off of the couch where he must have fallen asleep _…All everybody else sees are his rough attitude and the frown he always seems to have on his face, but even he has his cute sides sometimes_ , I thought, giving a fond smile as he made his way into the kitchen, rubbing at his bleary eyes.

Watching as he made his way to his seat beside me, I let a grin spread over my features as he unceremoniously flopped into his chair "Thanks for the food…" he mumbled sleepily before picking up his chopsticks and stuffing his face.

Grin widening as he munched on the extra crunchy Famima Chicken, I let out a small giggle, immediately catching his attention. Fixing me with an inquiring glare as he silently demanded an answer to his unasked question, his sharp, brown eyes widened slightly in shock as I reached over with a napkin and wiped away the few grains of rice that had gotten stuck to his cheek "You got food all over your face Onii-chan." I grinned as red hue made its way across the bridge of his nose and the tips of his ears "You haven't changed much since we were 3; you were always a messy eater, even Mom said–!" But at the accidental mention of one of our parents, I cut myself off, falling silent as Kentarou-nii noticeably stiffened beside me.

"…" Looking down into my lap to stare at my trembling hands, I bit my lips and exhaled softly before mustering the courage to lift my gaze and stare at the two seats around the dinner table; one across of my brother and myself and another at the head of the table. Both were, as we had come to expect and accept over the years, completely, unchangeably and perpetually empty.

"…" Squeezing my eyes shut as I pulled my knees up to my chest, I frantically combed through what little memories I had shared with my parents, desperately trying to find at least one memory, one phrase, one word, one thought, or even one moment, anything at all that might have indicated that our parents had ever wanted me… ever wanted _**us**_.

… _YOU USELESS GIRL! How can you be so nonchalant about taking second place?!_

… _ANOTHER fight, Kentarou?! Are you trying to make us a laughingstock?!_

… _Volleyball?! Don't make me laugh! Extra-curricular activities are for losers that have no real talent! For dunces like you!_

… _Going out with friends during the summer holidays? If that's a joke, it's not a funny one! You will spend your holidays studying every day until you can achieve any visible results!_

… _With children like you, how can you expect us to hold our heads high?!_

… _I knew it was a good idea to check the reliability of the products beforehand! We sued both the contraceptive pill company and the condom company and we won, but what was the point?! The damage had already been done…_

… _Neither of you should have been born…_

… _ **We**_ _ **never**_ _ **wanted you two…**_

"Kaede?! KAEDE?!"

"Hunh?!"

Feeling a strong pair of hands on my shoulders, shaking me out of my thoughts, I slowly took my hands away from my ears and turned to see the worried, brown eyes of my brother. Eyes softening slightly to reflect his relief, Kentarou-nii wrapped his arms tightly around me, pinning my arms to my sides as he rested his head on my shoulder protectively "…Forget about them." Eyes widening at the extremely bitter tone he used, I watched mutely as he lifted his face to meet my gaze, sharp brown eyes boring fiercely into mine "They never wanted us and we never asked to be born to them, but both of us must've done something really bad in our past lives because here we are."

"…Onii-chan…" but that was all I got out before he pressed a finger to my lips, immediately silencing me. Taking a deep breath, Kentarou-nii let out a long, calming sigh before reaching up to softly cup my cheeks, gently wiping away tears that I didn't even know had started to fall.

Not looking away from me, dark amber clashing with ochre, Kentarou-nii leaned forward, gently pressing a kiss to my forehead. Still feeling the lingering warmth from his affectionate gesture long after he had pulled away, I nodded, silently promising to keep quiet until he had finished saying what he had to say. Usually sharp, canine-like eyes softening as he pressed his forehead against mine, he closed his eyes as he continued where he had left off.

"My point is, they're never gonna want us and well… I can't speak for you, but I don't think I'd ever want them. But we were born into this together, so we still have each other and I'll always be there for you even if a time when you don't want me comes." Pulling away, Kentarou-nii gave another sigh "Don't ever forget that alright?"

"Mm-mm, I won't forget." Snuggling into my brother's chest as he wrapped his arms around me protectively, I gave a few giggles at his impromptu speech "You know… I like you better when we're alone because you don't put up a Mr. Toughest-guy –on-the-block front and you just act yourself…" I smiled, closing my eyes contentedly as he rested his chin over my head, letting out a small _Che_ in the process.

"Deal with it. I'm your older brother, so when idiots like Oikawa today think they can get cozy with my little sister, I'm going to prove them dead wrong."

"…"

"…What?!"

"…You say you're older, but we're twins, so you're only older by 4 minutes."

"…Shut up."

 _~The end of chapter 1 xD~_

Author's Note:

Heya! I'm still alive! :D It was really hard to keep Mad Dog-chan in character… actually, I think I failed and made him OOC but oh well; I like the idea of Kyoken-chan being a protective older brother! :D

Please comment, fave or follow if you liked this! xD

Anything is fine including constructive criticism and I'll update based on how much attention this story gets :D


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